Transformer Calculator
Calculate transformer parameters such as turns ratio, voltage, current, and power based on primary and secondary values.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Transformer Calculator
This calculator uses the ideal transformer equations: Vp / Vs = Np / Ns = Is / Ip and power conservation (VA).
- Enter at least three known values from the six main fields: Primary/Secondary Voltage (V), Turns (N), or Current (I).
- Optionally enter Power (VA) to override automatic calculation. Leave blank to auto-compute.
- All values must be positive numbers (decimals allowed). No unit conversion needed—use consistent units (e.g., volts, amps).
- Click "Calculate" to compute the missing parameters. Results show below with the formula used.
- Click "Clear" to reset all fields.
Tip: The calculator works for any transformer (step-up or step-down). Ensure at least one pair of related values (e.g., Vp & Vs or Np & Ns) for accurate turns ratio.
Previous Results
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Frequently Asked Questions
The turns ratio is the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. It determines how voltage and current are transformed.
Yes, for an ideal transformer, power (VA) is the product of voltage and current on either side. Our calculator can compute power if you provide primary or secondary voltage and current.
The calculator will use all valid inputs and compute missing values, but if there are conflicts, it may produce inconsistent results. For best accuracy, provide exactly three known values.